1. Field of the Invention
The invention relates to a multi-level fall protection system for a structure under construction and a method for providing such a system. More particularly, the invention relates to a multi-level fall protection system for a structure having multiple reinforced concrete decks, wherein flexible support lines are anchored to vertical support posts which extend between multiple decks, thereby providing fall prevention and/or fall arrest capabilities on multiple levels of the structure.
2. The Prior Art
Presently-used measures for preventing and/or arresting falls during high rise construction include wood planking loosely set in supports around the perimeter of a floor under construction, and harness systems worn by workers which are tethered to a support line consisting of a strap secured to an eye protruding out of the poured concrete. Other systems include horizontal netting supported by poles extending out from the construction site. These nets however are meant to stop and catch falling debris, not personnel.
The following references, the disclosures of which are incorporated herein by reference, relate to various fall protection systems.
U.S. Patent Application Publication No. 2001/0032435 to Austin describes a portable fall-arrest system temporarily attached to the reinforced concrete deck of a structure under construction. Threaded shafts are threaded into internally threaded inserts embedded in the concrete flooring or inserted through holes formed in the concrete flooring and secured with flanged nuts. Stanchions having a tubular posts and base plates are placed over the threaded shafts and a safety cable is strung between connector plates on two or more stanchions.
U.S. Pat. No. 6,691,826 to Dean describes a safety apparatus for construction workers working in elevated locations. The apparatus includes anchor members in the form of support posts which have flanged bases at their lower ends for clamping to an I-beam flange using a nut and bolt arrangement. Each support post has a radially extending lug on its upper end with an opening defined therein for receiving or securing a safety line. As shown in U.S. Pat. No. 7,048,090 to Dean et al., the support posts can have an I-shaped cross sectional configuration and can be clamped to a precast concrete structure, such as a concrete tilt panel.
U.S. Pat. No. 6,779,630 Choate shows a rebar stanchion horizontal lifeline fall arrest system wherein elongated tubular stanchions are slid over a section of rebar projecting from a reinforced concrete floor. The stanchions are supported with flexible guy members secured to additional projecting sections of rebar and a stanchion head slips over the top of the stanchion for supporting a cable lifeline.
U.S. Pat. No. 4,037,824 to Whitmer shows a safety post with a horizontal leg adapted to be detachably clamped to a structural beam and an integral vertical leg for retaining a safety cable.
U.S. Pat. No. 6,053,281 to Murray shows a safety rail system for installing around the perimeter of a rooftop work site. The system includes a plurality of vertical stanchions having links for receiving a safety cable tensioned with a winch. Each stanchion is supported in a sleeve portion of a hinged base plate and secured with a locking pin. The base plates are attached with appropriate fasteners to a vertical wall surface of the building and a second surface forming an edge with the vertical surface.
U.S. Pat. No. 6,763,910 to Cole shows a roof structure having safety stanchions mounted directly to a building roof for supporting a safety cable. The safety stanchions are secured to the roof structure at the intersections of the roof rafters and purlins.
U.S. Pat. No. 6,173,809 to Cole et al. shows a safety stanchion for supporting and anchoring a safety cable. The stanchion includes a tapered tubular post having an upper end for supporting a safety cable and a lower end attached to a support base that is mounted to a flanged structural beam.
U.S. Pat. No. 6,966,531 to Curtin shows a roof anchor for securing a safety line to the rafter of a timber roof frame.
Although a number of fall protection systems are known, a need exists for a multi-level fall protection system for a structure under construction which provides fall prevention and/or fall arrest on multiple levels of the structure, for example on multiple reinforced concrete decks or floors of a structure. Moreover, a need exists for a multi-level fall protection system which can be quickly and easily assembled, adapted to the particular structure as it is constructed, disassembled and re-used on additional structures.